A. Yildiz

Effect of grain size and strain on the bandgap of glancing angle deposited AZO nanostructures

Vertical and tilted nanorod arrays of Al-doped ZnO were deposited by glancing angle deposition method at room temperature. The morphologies of the samples were varied by adjusting the rotation speed of the substrate. The applicability of various analytical methods was considered in order to understand the structural results. Analysis of X-ray diffraction data showed that the most suitable evaluation of some structural parameters was performed with a ‘strain profile’ model. The values of the grain size and strain obtained from the best fits of this model to the experimental data were reasonable. The bandgap increased with decreasing grain size and increasing strain for the samples. The change in bandgap of the samples was explained by our detailed structural analysis.

Carrier transport in In-doped CuO thin films

Temperature-dependent conductivity and thermopower measurements are carried out for undoped and In-doped CuO thin films. We investigate the effects of In-doping on carrier transport properties of CuO thin films in the temperature range of 300 < T < 400 K. Carrier transport is dominated by simple thermally activated conduction in the undoped film. On the other hand, small polarons play an essential role in the carrier transport properties in the In-doped films. By increasing the In content, the conduction behaviour transits from adiabatic limit to the non-adiabatic limit, and the conductivity decreases.

Electron transport in Al-Cu co-doped ZnO thin films

To investigate the influence of varying Al content on structural, optical, and electrical properties of ZnO thin films, Al-Cu co-doped ZnO thin films with fixed Cu content at 1 wt. % and different Al contents (1, 3, and 5 wt. %) were successfully synthesized on glass substrates using a sol-gel process. The results indicated that the varying Al content affects not only the grain size and band gap but also the electrical conductivity of the films, and a linear relationship was found between the band gap and strain values of the films. The temperature-dependent electrical conductivity data of the films demonstrated that electron transport was mainly controlled by the grain boundaries at intermediate and high temperatures, whereas it was governed by Mott-variable range hopping at low temperatures. Additionally, 3 wt. % Al content improved the electrical conductivity of Al-Cu co-doped ZnO by lowering the trap density and enhancing the hopping probability.

Influence of the spin acceleration time on the properties of ZnO:Ga thin films deposited by sol–gel method

AbstractA detailed study of the structural, morphological, optical, and electrical properties of the spin-coated Ga-doped ZnO (GZO) films in which these properties are altered by varying the spin acceleration time (tacc) was undertaken. The results showed that, by varying tacc, there is no significant variation in crystal size, and band gap energy of the films, while some physical parameters such as strain

Surface wettability of titania thin films with increasing Nb content

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Fluctuating in the hopping rate of CuO thin films with respect to substrate temperature

ε, surface roughness (RMS), and porosity (P) are remarkably varied. By increasing tacc from 0 to 8 s,

Effects of Co and Cu dopants on the structural, optical, and electrical properties of ZnO nanocrystals

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